/*
 *  md5.jvs 1.0b 27/06/96
 *
 * Javascript implementation of the RSA Data Security, Inc. MD5
 * Message-Digest Algorithm.
 *
 * Copyright (c) 1996 Henri Torgemane. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for any purposes and without
 * fee is hereby granted provided that this copyright notice
 * appears in all copies. 
 *
 * Of course, this soft is provided "as is" without express or implied
 * warranty of any kind.

    This version contains some trivial reformatting modifications
    by John Walker.

 */

function array(n) {
    for (i = 0; i < n; i++) {
        this[i] = 0;
    }
    this.length = n;
}

/* Some basic logical functions had to be rewritten because of a bug in
 * Javascript.. Just try to compute 0xffffffff >> 4 with it..
 * Of course, these functions are slower than the original would be, but
 * at least, they work!
 */

function integer(n) {
    return n % (0xffffffff + 1);
}

function shr(a, b) {
    a = integer(a);
    b = integer(b);
    if (a - 0x80000000 >= 0) {
        a = a % 0x80000000;
        a >>= b;
        a += 0x40000000 >> (b - 1);
    } else {
        a >>= b;
    }
    return a;
}

function shl1(a) {
    a = a % 0x80000000;
    if (a & 0x40000000 == 0x40000000) {
        a -= 0x40000000;  
        a *= 2;
        a += 0x80000000;
    } else {
        a *= 2;
    }
    return a;
}

function shl(a, b) {
    a = integer(a);
    b = integer(b);
    for (var i = 0; i < b; i++) {
        a = shl1(a);
    }
    return a;
}

function and(a, b) {
    a = integer(a);
    b = integer(b);
    var t1 = a - 0x80000000;
    var t2 = b - 0x80000000;
    if (t1 >= 0) {
        if (t2 >= 0) {
            return ((t1 & t2) + 0x80000000);
        } else {
            return (t1 & b);
        }
    } else {
        if (t2 >= 0) {
            return (a & t2);
        } else {
            return (a & b);  
        }
    }
}

function or(a, b) {
    a = integer(a);
    b = integer(b);
    var t1 = a - 0x80000000;
    var t2 = b - 0x80000000;
    if (t1 >= 0) {
        if (t2 >= 0) {
            return ((t1 | t2) + 0x80000000);
        } else {
            return ((t1 | b) + 0x80000000);
        }
    } else {
        if (t2 >= 0) {
            return ((a | t2) + 0x80000000);
        } else {
            return (a | b);  
        }
    }
}

function xor(a, b) {
    a = integer(a);
    b = integer(b);
    var t1 = a - 0x80000000;
    var t2 = b - 0x80000000;
    if (t1 >= 0) {
        if (t2 >= 0) {
            return (t1 ^ t2);
        } else {
            return ((t1 ^ b) + 0x80000000);
        }
    } else {
        if (t2 >= 0) {
            return ((a ^ t2) + 0x80000000);
        } else {
            return (a ^ b);  
        }
    }
}

function not(a) {
    a = integer(a);
    return 0xffffffff - a;
}

/* Here begin the real algorithm */

var state = new array(4); 
var count = new array(2);
    count[0] = 0;
    count[1] = 0;                     
var buffer = new array(64); 
var transformBuffer = new array(16); 
var digestBits = new array(16);

var S11 = 7;
var S12 = 12;
var S13 = 17;
var S14 = 22;
var S21 = 5;
var S22 = 9;
var S23 = 14;
var S24 = 20;
var S31 = 4;
var S32 = 11;
var S33 = 16;
var S34 = 23;
var S41 = 6;
var S42 = 10;
var S43 = 15;
var S44 = 21;

function F(x, y, z) {
    return or(and(x, y), and(not(x), z));
}

function G(x, y, z) {
    return or(and(x, z), and(y, not(z)));
}

function H(x, y, z) {
    return xor(xor(x, y), z);
}

function I(x, y, z) {
    return xor(y ,or(x , not(z)));
}

function rotateLeft(a, n) {
    return or(shl(a, n), (shr(a, (32 - n))));
}

function FF(a, b, c, d, x, s, ac) {
    a = a + F(b, c, d) + x + ac;
    a = rotateLeft(a, s);
    a = a + b;
    return a;
}

function GG(a, b, c, d, x, s, ac) {
    a = a + G(b, c, d) + x + ac;
    a = rotateLeft(a, s);
    a = a + b;
    return a;
}

function HH(a, b, c, d, x, s, ac) {
    a = a + H(b, c, d) + x + ac;
    a = rotateLeft(a, s);
    a = a + b;
    return a;
}

function II(a, b, c, d, x, s, ac) {
    a = a + I(b, c, d) + x + ac;
    a = rotateLeft(a, s);
    a = a + b;
    return a;
}

function transform(buf, offset) { 
    var a = 0, b = 0, c = 0, d = 0; 
    var x = transformBuffer;
    
    a = state[0];
    b = state[1];
    c = state[2];
    d = state[3];
    
    for (i = 0; i < 16; i++) {
        x[i] = and(buf[i * 4 + offset], 0xFF);
        for (j = 1; j < 4; j++) {
            x[i] += shl(and(buf[i * 4 + j + offset] ,0xFF), j * 8);
        }
    }

    /* Round 1 */
    a = FF( a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
    d = FF( d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
    c = FF( c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
    b = FF( b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
    a = FF( a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
    d = FF( d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
    c = FF( c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
    b = FF( b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
    a = FF( a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
    d = FF( d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
    c = FF( c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
    b = FF( b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
    a = FF( a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
    d = FF( d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
    c = FF( c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
    b = FF( b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

    /* Round 2 */
    a = GG( a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
    d = GG( d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
    c = GG( c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
    b = GG( b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
    a = GG( a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
    d = GG( d, a, b, c, x[10], S22,  0x2441453); /* 22 */
    c = GG( c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
    b = GG( b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
    a = GG( a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
    d = GG( d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
    c = GG( c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
    b = GG( b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
    a = GG( a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
    d = GG( d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
    c = GG( c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
    b = GG( b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

    /* Round 3 */
    a = HH( a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
    d = HH( d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
    c = HH( c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
    b = HH( b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
    a = HH( a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
    d = HH( d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
    c = HH( c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
    b = HH( b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
    a = HH( a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
    d = HH( d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
    c = HH( c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
    b = HH( b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
    a = HH( a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
    d = HH( d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
    c = HH( c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
    b = HH( b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

    /* Round 4 */
    a = II( a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
    d = II( d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
    c = II( c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
    b = II( b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
    a = II( a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
    d = II( d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
    c = II( c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
    b = II( b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
    a = II( a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
    d = II( d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
    c = II( c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
    b = II( b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
    a = II( a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
    d = II( d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
    c = II( c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
    b = II( b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

    state[0] += a;
    state[1] += b;
    state[2] += c;
    state[3] += d;

}

function md5_init() {
    count[0] = count[1] = 0;
    state[0] = 0x67452301;
    state[1] = 0xefcdab89;
    state[2] = 0x98badcfe;
    state[3] = 0x10325476;
    for (i = 0; i < digestBits.length; i++) {
        digestBits[i] = 0;
    }
}

function md5_update(b) { 
    var index, i;
    
    index = and(shr(count[0],3) , 0x3F);
    if (count[0] < 0xFFFFFFFF - 7) {
      count[0] += 8;
    } else {
      count[1]++;
      count[0] -= 0xFFFFFFFF + 1;
      count[0] += 8;
    }
    buffer[index] = and(b, 0xff);
    if (index  >= 63) {
        transform(buffer, 0);
    }
}

function md5_finish() {
    var bits = new array(8);
    var padding; 
    var i = 0, index = 0, padLen = 0;

    for (i = 0; i < 4; i++) {
        bits[i] = and(shr(count[0], (i * 8)), 0xFF);
    }
    for (i = 0; i < 4; i++) {
        bits[i + 4] = and(shr(count[1], (i * 8)), 0xFF);
    }
    index = and(shr(count[0], 3), 0x3F);
    padLen = (index < 56) ? (56 - index) : (120 - index);
    padding = new array(64); 
    padding[0] = 0x80;
    for (i = 0; i < padLen; i++) {
      md5_update(padding[i]);
    }
    for (i = 0; i < 8; i++) {
      md5_update(bits[i]);
    }

    for (i = 0; i < 4; i++) {
        for (j = 0; j < 4; j++) {
            digestBits[i * 4 + j] = and(shr(state[i], (j * 8)) , 0xFF);
        }
    } 
}

/* End of the MD5 algorithm */
